“The eight Accent colors are really an expansion of the old version of Appearances; these options change the look of things like drop-down menus, checkboxes and more. They are available in both the Light and Dark Appearances, and can really change the feel of macOS.”

The most obvious change to macOS coming later this year is in the inclusion of Dark Mode. When Apple redesigned macOS back in 2014 with Yosemite, it included a less ambitious version of the feature. Here’s a bit from my review:

The last point, “Dark Mode is content-focused” should sound familiar to anyone who was around during the iOS 7 transition, or who was paying attention when OS X Yosemite was introduced. Your eye is naturally drawn to the thumbnails in Finder, and Preview’s window chrome doesn’t compete with the open document. Note that this is not the same as Vibrancy, which allows a lot more of the background color through the material used in places like Finder’s sidebar, Spotlight, Notification Center and more: In Mojave, clicking “Reduce transparency” in the Accessibility preference pane disables Vibrancy as before, and lessens the impact of Desktop Tinting, but doesn’t banish it altogether. Some apps won’t make the change, and much of the web — this website included — looks shockingly bright in the context of macOS Mojave: